The invention relates generally to the thermal management of battery-based power systems, and more particularly to draining coolant in the event of a coolant breach within such a system.
Lithium-ion and related batteries, collectively known as a rechargeable energy storage system (RESS), are being used in automotive applications as a way to supplement, in the case of hybrid electric vehicles (HEVs), or supplant, in the case of purely electric vehicles (EVs), conventional internal combustion engines (ICEs). The ability to passively store energy from stationary and portable sources, as well as from recaptured kinetic energy provided by the vehicle and its components, makes batteries ideal to serve as part of a propulsion system for cars, trucks, buses, motorcycles and related vehicular platforms. In the present context, a cell is a single electrochemical unit, whereas a battery is made up of one or more cells joined in series, parallel or both, depending on desired output voltage and capacity.
Because an energized battery cell, module, section or pack is capable of producing large amounts of energy, temperature (and the removal of excess quantities thereof) is one of the most significant factors impacting both the performance and life of a battery. To keep temperature excesses from occurring, cooling systems are frequently integrated into a RESS based platform. In one conventional form, the cooling system circulates a liquid-based coolant using alcohol, water or a combination thereof. Typically, the RESS is configured to promote as much contact between the heat-generating portions of the individual cells and the coolant as possible. However, the same cooling system that provides necessary heat-removal may—in the event of an internal failure of one or more battery cells due to a crash event, component wear or a manufacturing defect—lead to leakage of the coolant onto sensitive electrical components (such as circuit boards or the like) in and around the individual cells. Such leakage may provide an efficient and unintended path for the conveyance of the electrical current being generated by the batteries such that in one undesirable form, the leaked coolant may lead to a short circuit of these sensitive system components.
It would be beneficial to provide early detection of loss of coolant into the battery following an accident or related incident to avoid harm to a RESS. It would be further beneficial to implement automated corrective actions in the event of a detected or imminent leakage of coolant into sensitive portions of a battery system.